The present invention generally relates to communications systems and, more particularly, to wireless systems, e.g., terrestrial broadcast, cellular, Wireless-Fidelity (Wi-Fi), satellite, etc.
In many wireless communications systems, the key problem is that a receiver may be able to receive the transmission of some of the channels (or signals) but not all of them. For example, in a terrestrial broadcast television (TV) system in the United States, a city may typically have 5 to 15 terrestrial transmitters that are geographically separated, each terrestrial transmitter broadcasting content on a particular channel (or channels). However, a TV set may only be able to receive a subset of the channels being broadcast in a given geographical area because of the geographical location of the TV set. Indeed, for a modern digital communication system like the ATSC-DTV (Advanced Television Systems Committee-Digital Television) system (e.g., see, United States Advanced Television Systems Committee, “ATSC Digital Television Standard”, Document A/53, Sep. 16, 1995 and “Guide to the Use of the ATSC Digital Television Standard”, Document A/54, Oct. 4, 1995), it is well known that the coverage for a given area varies depending on the location of the TV set. This is further illustrated in FIG. 1. A geographical area includes terrestrial ATSC-DTV transmission towers T1, T2, T3 and T4, for broadcasting content associated with channels 1, 2, 3 and 4, respectively. (For the purposes of this example, it is assumed that each transmission tower only broadcasts programming for a single channel.) In this geographical area, two TV sets, TV set 10 and TV set 20, are located. As illustrated in FIG. 1 by the dotted lines arrows, TV set 10 is only able to receive a subset of the available channels, i.e., channels 2, 3 and 4. Likewise, the dashed line arrows of FIG. 1 illustrate that TV set 20 is only able to receive channels 1, 2 and 4.
There is no solution today that can mitigate this problem.
Indeed, this problem also affects the offering of other services in a wireless network. As an illustration, again consider an ATSC-DTV system. Today, an ATSC-DTV system offers about 19 Mbits/sec (millions of bits per second) for transmission of an MPEG2-compressed HDTV (high definition TV) signal (MPEG2 refers to Moving Picture Expert Group (MPEG)-2 Systems Standard (ISO/IEC 13818-1)). As such, around four to six standard definition TV channels can be safely supported in a single physical transmission channel (PTC) without congestion. Additionally, enough bandwidth remains within this transport stream to provide several additional low-bandwidth non-conventional services, or auxiliary services, such as weather reports, stock indices, headline news, home shopping, etc. In fact, due to improvements in both MPEG2 encoding and the introduction of advanced codec (coder/decoder) technology (such as H.264 or VC1), even more additional spare capacity is becoming available in a PTC for use in offering auxiliary services.
However, the above-described problem inhibits the offering of a guaranteed class of service for these auxiliary services over a defined geographical region.